This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Lipid kinase mutations play an important role in driving cancer growth. We propose to explore the underlying molecular mechanisms of amino acid changing mutations seen in breast cancers in the Class I lipid kinase PIK3CA using the X-ray crystal structure of its homolog, the Class I lipid kinase PIK3CG. We request resources to run 10ns Langevin dynamics simulations of seven mutant and three wild-type structures with CHARMM to elucidate the structural changes that produce an abnormal, hyperactive protein in cancer.